/Engine/Source/Developer/SkeletalMeshUtilitiesCommon/Public/LODUtilities.h
SkeletalMesh: The skeletalmesh we want to optimize  LODIndex: The LOD we want to optimize  TextureMask: The texture containing the stripping mask. non black pixel strip triangle, black pixel keep them.  Threshold: The threshold we want when comparing the texture value with zero.
static bool StripLODGeometry ( [USkeletalMesh](API\Runtime\Engine\Engine\USkeletalMesh) * SkeletalMesh, const int32 LODIndex, [UTexture2D](API\Runtime\Engine\Engine\UTexture2D) * TextureMask, const float Threshold )